Doctor mechanism for papermaking rolls and cylinders



April 8, 1947. F. H. GOYETTE 2,418,705

DOCTOR MECHANISM FOR PAPERMAKING ROLLS AND CYLINDERS Filed Dec. 3, 1943 2 Sheets-Sheet 1 Es. 6'. }\w

INVENTOR Educ/5 Goy 8 BY 0 .7 M 1 M ATTORNEY April 8, 1947. F. H. GdYETTE 12,418,705

DOCTOR MECHANISM FOR PAPER-MAKING ROLLS AND CYLINDERS Filed Dec. 3, 1945 2 Sheets-Sheet. 2

tNVENTOR 6'; J0 BYHa/ICLS Gofefl'e ATTORNEY- Patented Apr. 8, 1947 DOCTOR MECHANISM FOR PAPERMAKIN ROLLS AND CYLINDERS Francis H. Goyette, Worcester, Mass., assignor to Lodding Engineering Corporation, Worcester, Mass., a corporation of Massachusetts Application December 3, 1943, Serial No. 512,763-

2 Claims.

The present invention relates to devices known in the paper making art as doctors or scrapers, such devices being customarily employed in connection with rotating calender rolls, drier cylinders, and the like, for the purpose of cleaning the surfaces of such rolls and cylinders, or removing a web of paper therefrom, ask: the manufacture of crepe paper.

In Lodding Patent No. 1,892,214, issued December 27, 1932, there is shown and described a doctor mechanism of the above indicated type, characterized by the provision of a thin flexible doctor blade carried by a relatively stiff holder. In operation, the holder of the Lodding doctor is adapted to apply pressure in a direction opposite to reactions set up along the edges of the blade by the surface which is being doctored'and by a portion of the rigid holder, with the mechanism also providing means for feeding the doctor blade bodily, from within the holder, in

order to compensate for wear of the scraping edge of the blade. The object of the present invention is to provide certain improvements in the above-described patented construction as regards the manner of supporting and applying pressure to the blade, as well as for compensating for wear of the blade in use. Briefly stated, the present invention contemplates the provision of a holder for the doctor blade so constructed that the holder itself may be readily adjusted to compensate for wear of the blade, to such an extent that the loss of material is worn out and discarded blades is reduced to an absolute minimum. Since doctor blades are usually made of metal, the mechanism of the present invention, by increasing the amount of usable material through adjustment for blade wear in the holder itself, represents a distinct advance in the art over previous constructions.

The above and other advantageous features of the invention will hereinafter more fully appear from the following description, with reference to the accompanying drawings, in which- Fig. 1 is a view in end elevation of a doctor mechanism embodying the present invention, showing the doctor cooperating with a portion of a roll surface, for the production of crepe paper.

Fig. 2 is a vertical sectional view of the mechanism of Fig. 1, showing the holder adjusted to compensate for wear of the blade.

Fig. 3 is a view similar to Fig. 1, showing a stillfurther adjustment of the holder.

Fig. 4 is a perspective view of a portion of the base member oi'the holder removed from the Fig. 6 is a diagrammatic view illustrating the manner of grinding the creping doctor which necessitates the holder adjustments shown in Figs. 1, 2 and 3.

. Fig. 7 is a view in end elevation of a modified form of doctor holder embodying the'invention, for mounting a different type of doctor blade.

Fig. 8 is a sectional view of the mechanism shown in Fig. '7, illustrating an adjustment for blade wear.

Figs. 9 and 10 are perspective views showing portions of the holder members removed from the assembly of Fig. '7.

Referring to the drawings, a portion of the surface of a roll or cylinder is indicated at l, and a holder 2 embodying the invention. is carried by an arm 3 turnable about a pivot 4 with respect to the roll I. Suitable means, not shown, are provided for imparting a turning movement to the arm 3 about its pivot 4, thus tending to swing the holder 2 in the direction of the'arrow to bring-a doctor blade .5 into engagement with the moving surface of the roll I. The blade 5 is made of any suitable thin flexible material such as steel, brass, or a synthetic composition such as Bakelite.

As previously pointed out, the form of the invention shown in Fig. 1 contemplates the use of the blade 5 for the production of crepe paper, with the scraping edge of the blade serving to remove a paper web W from the surface of the roll I, as the latter moves in the direction of the arrow. As indicated in the enlarged showing of the blade 5 in Fig. 6, the edge of the blade is ground at an angle which determines the degree of crinkle in the web W, and in practice such scraping blades have to be reground frequently,

owing to the tendency of the blade to flatten where it bears on the roll, as indicated on an exaggerated scale in dotted lines.

In view of the above described characteristics vention provides an improved blade holder adapted for ready adjustment, so as to make possible the utilization of all available blade material before discarding a blade.

As best shown in Figs. 1, 4 and 5, the blade holder 2 comprises a base member 8 and a clamping member l, with both members extending across the full width of the roll I.

The base member 6 provides a number of longitudinal grooves 8 extending along its upper surface, and the under side of the clamping member i provides a single projecting tongue 9 adapted to fit freely into any one of the grooves 8.

The members 5 and 1 are secured together, with the tongue 9 in one of the grooves 8, by means of bolts screwed into threaded openings ll provided in the clamping member 1. It is to be noted in Fig. 4 that the base member 6 provides a series ofequally spaced openings l2 extending between the grooves 8, these openings i2 being unthreaded and of such diameter as to freely receive the bolts l0. Thus the two members 6 and l of the holder 2 can be secured together with the tongue 8 in any one or the three grooves 8, as shown in Figs. 1, 2 and 3,,respectively.

When the holder members 6 and l are secured together by the bolts l0, their opposed surfaces are held apart by a spacing plate 13. This plate, as best shown in Fig. 5, is of such width as to extend between the left hand edge of the clamping member '1 and the tongue 9, with the plate (3 being held in position by the bolts l0 passing through openings I 4 provided in the plate. Therefore, the right hand edge of the holder 2 provides a space I 5 adapted to freely receive one edge of the doctor blade 5.

For installing a new doctor blade 5, theholder 2 is assembled as shown in Fig. 1, with the tongue 9 of the member I received in the groove 8 farthest removed from the right hand end of the base member 6. The blade 5 having-been inserted in the space i5, the assembled holder is mounted on the pivotedarm 3 by inserting the ungrocved end of the member 6, which extends beyond the member 1, into a space provided between a seat l6 on the arm 3 and an overlying clamping bar IT. The bar I! is secured to the arm 3 by a bolt I 8, so that when the holder and its blade have been mounted and a force is applied to the arm 3 tending to turn it in a counterclockwise direction, the right hand edge of the blade 5 will be applied to the moving surface of the roll I, with the blade 5 remaining seated in the holder 2 as long as the pressure is applied by the arm.

Let it now be assumed that continued operation of the blade 5 as a creping doctor has resulted in the wear previously described with reference to Fig. 6, so that it is necessary to replace the blade. When this occurs, the arm 3 is swung away from the roll I to release the blade pressure, so that the assembled holder can be readily removed from between seat l6 and the clamping bar H. Should it be desired to employ the same blade 5, the latter is removed from the holder and its edge reground as previously described with reference to Fig. 6. v

Before replacing the reground blade in the holder 2, the latter is adjusted by unscrewing the bolts ID from the openings H, so that the clamping member I can be moved from the position of Fig. l to the position of Fig. 2, with the tongue 9 received in the middle groove 8. The bolts [0 are then replaced and the holder with the reground blade received in the space I5 is mounted as shown in. Fi 2. With the holder 2 in its.

. 4 adjusted position, it is to be noted that the distance between the scraping edge of the reground blade 5 and the point of application of pressure to the blade by the forward edge of the base member 6 is substantially the same as in Fig. 1, where a new blade is being used.

When it becomes necessary to regrind the blade 5 a second time, the holder 2 is removed and again reassembled with the tongue 9 in the extreme right hand groove 8, as shown in Fig. 3. With this second adjustment of the holder to mount a twice reground blade, it is to be noted that the edge of the blade again bears the same relation to the forward edge of the base member 6. Generally speaking, the spacing between the grooves 8 of the base member 8 is substantially equal to the amount of material that is.removed from the edge of the blade by each regrinding, so that the blade operates in substantially the same manner after successive regrindings.

While for purposes of illustration, the adjustments of a given holder 2 have been described with reference to a given blade 5, obviously several holders and blades can be employed in connection with a given roll i to obtain the same results. For example, three separate holders 2 can be always maintained with the three diii'erent settings of Figs. 1, 2 and 3, so as to receive reground blades as well as new blades. When any one of the three holders is in operation, the other two holders will be held in reserve, so that when a blade becomes worn, it can be quickly replaced by a holder with another blade which may be either new or reground. When employing such a practice of rotating the use of holders, a reground blade will be placed in a holder previously adjusted to suit the extent of regrinding, so that with one or more holders and blades in reserve, the replacement of a worn blade can be quickly accomplished. The net result of utilizing holders adjusted to suit the extent of regrinding of different blades results in each individual blade being utilized to the fullest possible extent, there- 45 by reducing the waste of metal in discarded blades to an absolute minimum.

Referring now to Figs. 7 to inclusive, there is shown a modified form of blade holder 2', constructed to receive a different type of blade I8 50 that is relatively stiff compared to the blade 5, with the blade [9 being applied to a roll 20. The modified form of holder 2' comprises a base member 2i secured to a pressure applying arm 22 by a bolt 23, with a clamping member 24 secured to 55 the under side of the base member 2| by screws 25. The lower face of the member 2| provides spaced grooves 26 opposing a seat 21 provided by the member 24, and as best shown in Fig. 10, the inner edge of the blade I9 provides a series of so studs 28 adapted to be received in one of the grooves 26.

When the blade i 9 is new, it is mounted in the holder 2' with its studs 28 received in the left hand groove 28 of the member 2! as shown in Fig.

65 7. When the blade 19 is applied to the roll 28 moving in the direction of the arrow, the blade is held in proper position with respect to the holder seat 2'! by cooperation between the blade studs 28 and the left hand groove 26. When continued use of the blade l9 has worn it to the extent that it must be replaced, the worn blade is remounted with respect to the holder by positioning the blade 19 with its studs 28 received in the right hand groove 26, as shown in Fig. 8. 7 The scraping edge of the remounted blade then 6.! bears the same relation to the outer end of the holder as does the new blade shown in Fig. '7. When employing a remounted blade as shown in Fig. 8, the holder is provided with a spacer bar 29 providing studs 30 for reception in the left hand groove 26 of the base member 2|.

I claim:

1. A doctor mechanism for paper-making rolls and cylinders comprising in combination, a pivo p ally mounted holder providing an open slot for receiving one edge of a doctor blade having its other edge bearing on a rotating surface by application of a turning movement to said holder, with said holder consisting of a base member providing a number of spaced grooves extending parallel to the axis of the surface being doctored, a cooperating clamping member providing a tongue for reception in one of said grooves, with one side of said tongue determining the depth of the blade receiving slot of said holder, and means for maintaining said holder members together to mount blades of different widths, in accordance with the selected location of said tongue in one of said grooves of the base member.

2. A doctor mechanism for paper-making rolls and cylinders comprising in combination, a pivotally mounted holder providing an open slotfor receiving one edge of a doctor blade having its other edge bearing on a rotating surface by application of a turning movement to said holder, with said holder consisting of a base member providing a; number of spaced grooves extending parallel to the axis of the surface being doctored, a cooperating clamping member providing a tongue for reception in one of said grooves, with one side of said tongue determining the depth of the blade receiving slot of said holder, openings provided by said base member between said grooves. and fastening members extending through certain of said openings into said clamping member for securing it to said base member with said tongue in a selected groove.

FRANCIS H. GOYE'I'TE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,331,840 Bates Feb. 24, 1920 1,907,623 Vickery May 9, 1933 1,696,119 Heisel c Dec. 18, 1928 FOREIGN PATENTS Number Country Date 674,076 German Apr. 5, 1939 459,543 British Jan. 11, 1937 

